This is a Pro only feature.
Some CAD files might contain non-standard units, coplanar faces, or inconsistently oriented faces. You can force SketchUp to automatically analyze and repair these issues during the import process.
Geometry
The Geometry section of the AutoCAD DWG/DXF Import Options dialog box contains options to configure the appearance of the exported VRML file.
Merge Coplanar Faces
Planes can import into SketchUp with triangulated lines. Removing these lines manually can be tedious. The Merge coplanar faces option is used to have SketchUp automatically remove these lines.
Orient Faces Consistently
The Orient faces consistently option is used to analyze the direction of imported faces and orient these faces so that they are uniform in direction.
Scale
Some CAD formats, such as DXF, save data in generic units. The Scale section of the AutoCAD DWG/DXF Import Options dialog box contains options to configure the units for the imported file.
Units
Select the unit type used in the original CAD file to import geometry at the correct scale.
Preserve Drawing Origin
The Preserve drawing origin option is used to define where the DWG/DXF file will be placed when it is inserted into a SketchUp file. Check this box if you want to place the DWG/DXF file at the origin, as originally defined in the DWG/DXF file. Do not check this box if you want the DWG/DXF file to be placed near the SketchUp origin.